It is getting easier for parents to help their children on to the housing ladder with a number of schemes that don't involve having to hand over vast sums for a deposit. But read the small print carefully.

The latest, Barclays Family Affordability Plan, enables parent and child to pool their resources to secure a larger mortgage to buy a first place, or trade up to a bigger property.

Other schemes use the equity in mum and dad's property to secure a higher loan-to-value than would otherwise be available, or require parents to put money into a savings account which can be set against the loan in case things go wrong.

But some of these deals aren't for the faint-hearted, and people need to be very clear about what they are signing up to. The simplest, and most popular, way for parents to help their children, is to contribute towards a deposit. However, many parents don't have that sort of cash – but will have quite a lot of equity in their property.

Here we look at some of the different schemes:

Barclays Family Affordability Plan. You combine your income with that of your parents' by taking out a joint mortgage. All the incomes then count towards the calculations used to work out how much Barclays will lend. If the mortgage is approved all the parties named on the documents are liable for the monthly payments. However, the parents don't need to be named on the deeds (unless they want to be).

Here's how it works. Jo has her eye on a £150,000 house. She has a deposit of £15,000, which would mean a mortgage of £135,000. But Jo's income is £25,000, so if she was going it alone the standard mortgage that Barclays would look to offer would be a maximum of £100,000.

However, by bringing her father Fred's £35,000-a-year income into the equation she could obtain a £180,000 (subject to the usual checks).

Setting up a mortgage like this has advantages, according to the bank. Firstly, as Fred isn't a co-owner, he won't incur any capital gains tax in the event of Jo's house being sold if he already owns his own home.

Also, a few years down the line when Jo can, hopefully, afford the mortgage without her father's help, it is fairly easy to remove Fred's name by remortgaging – there is no transfer of equity involved.

David Hollingworth at broker London & Country says that with this type of arrangement the lender will want to know how old the parent is at the outset, how old they will be when the mortgage ends and, if that is beyond normal retirement age, can they provide evidence of a sufficient income to meet the affordability criteria? He adds: "The absolute maximum age is usually 75, even if they can show income beyond normal retirement age."

Barclays tends to want a mortgage paid off by the time a borrower is 70, but says: "If it goes beyond retirement our policy is that we will look at the income stream." The Family Affordability Plan is available in England and Wales on any Barclays mortgage.

There are a number of deals that make use of the value tied up in the parental home. However, Mark Harris at broker SPF Private Clients, says: "It's important to seek advice, particularly if the lender is taking a 'charge' over your property. Depending on the details of the guarantee you may be restricted from borrowing in your own right until the restriction is lifted, so it's important to understand what you are getting into beforehand."

New bank Aldermore offers the Family Guarantee Mortgage, a 100% mortgage which needs no deposit, though the buyer must find a relative – a parent, step-parent or grandparent – willing to guarantee any borrowing above 75%.

Aldermore takes a charge over the guarantor's home. This will be up to 25% of the value of the property being bought (but will never exceed 25%, says the bank). If the borrower fails to keep up with their payments the guarantor is liable for the value of the guarantee. After 10 years the guarantee expires, leaving the son/daughter with sole responsibility for the loan.

Buyers will need to prove they can afford monthly payments on the whole amount borrowed, while the guarantor – who must be under 60 at the outset – will also be expected to have some form of income. The interest rate is 5.98%, fixed for either two or three years. The maximum loan size is £250,000.

Aldermore gives the example of "David and Alison", who have found a house costing £140,000. They have no deposit so they need to borrow the full amount. Alison's parents agree to give a guarantee for the amount of the loan above 75%. Her parents' home is valued at £270,000, with a mortgage of £62,000 outstanding, so they have more than enough equity to support the guarantee, which equates to £35,000 (25% of £140,000).

The Parental Assistance Mortgage Scheme from Bath building society, available in England and Wales, allows people to borrow up to 95% of the property's value, though if the LTV is greater than 80%, the society will require a charge over the parents' home. This will be for a maximum of 15% of the amount being borrowed.

Borrowers can get a three-year fix starting from 4.99% with a 0.5% fee (minimum £599).

Another option is the Family First Guarantor Mortgage from Surrey-based National Counties building society. This also allows people to borrow up to 95%, though if the child's LTV exceeds the society's standard 75% maximum, a parent or grandparent is required to grant the society an unlimited charge over their home. A two-year fixed-rate mortgage priced at 4.69% is available, with a £495 fee.

Lloyds TSB's Lend a Hand deal, you can take out a mortgage with a deposit of 5%, and benefit from the sort of rates available to those able to put down much more – provided someone else (typically mum or dad) puts up their savings as security. Your helper will need savings equal to 20% of the property's value (your deposit and their savings must add up to 25%).

The rate is 4.49%, or 4.29% if you are a Lloyds current account customer, fixed for three years, with a £995 fee. With no fee, the rate is 5.09%/4.89%. The helper has to put their money into a special savings account paying a fixed 3.7% (2.91% after tax) for 42 months.